In the past, writing instruments termed fountain pens comprised a hollow barrel housing a flexible well which acted as a plunger to draw liquid ink into the well. The ink was dispensed through a nib. A cover was removably attached to the barrel to cover the nib when the pen was not in use.
The fountain pen was replaced by a ball point pen having a writing point in the form of a ball, fed with a rather viscous ink from a cartridge-type reservoir. A propel-repel type mechanism was employed to draw the writing point into and out of the barrel of the writing instrument.
Recent developments in liquid ink cartridges has permitted fiber tips to be attached to the writing ends of ink cartridges. The problem presented is to provide a barrel construction wherein the ink cartridge may be securely housed, be ready for instant use, protect the fiber tip against accidental use, reduce ink evaporation to a minimum and provide easy and rapid means for replacing the ink cartridge.